Natural hairstyle modeling and animation

In this paper, we develop a hairstyle modeling and animation technique spec ifically designed for human hairs, and we report several experimental resul ts. Using simplified cantilever beam model and one-dimensional projective d ifferential equations of angular momenta, we give a practical solution to t he problem of enormous complexity. Even though our hair animation algorithm is an approximate solution, it includes all the relevant dynamic elements such as gravity, wind, inertia, air-resistance, hair-to-head, and hair-to-h air friction forces. Collision is an important element that makes a collect ion of hair strands look like hair. We develop an accurate but efficient ha ir-to-head and hair-to-hair collision detection and treatment algorithm. Th e algorithm produces quite realistic results; still it runs at an interacti ve speed. An interesting contribution of our algorithm is that it unifies h airstyle modeling and animation into a single equation, so that (1) hairsty ling can be done under the effects of gravity and other internal or externa l forces, and (2) original hairstyle is more or less restored even after th e initial hair is tangled by the application of external forces or head mov ements. (C) 2001 Academic Press.